A Piece of the Variable
In the Star Trek episode, “A Piece of the Action”, Kirk and his crew travel to Sigma Iotia II, a planet last visited before the Prime Directive of non-interference existed. Well, they left behind a book, Chicago Mobs of the Twenties, which the Iotians took as a holy guide, to be imitated and followed even if they didn’t quite understand it, a sort of sci-fi cargo-cult. Cue the crew of the Enterprise being threatened with Tommy Guns and guys doing bad Al Capone impressions.
Michael’s co-worker may have fallen into a similar trap. An advanced developer came to him, and gave him a rule: in PHP, since variables may be used without being declared, it’s entirely possible to have an unset variable. Thus, it’s a good practice to check and see if the variable is set before you use it. Normally, we use this to check if, for example, the submitted form contains certain fields.